[This post was originally published April 2013. It was completely updated and republished in October 2013. Most recent update: October 11, 2013.]

The impending retirement of Windows XP and Office 2003 shouldn’t come as a surprise to anyone. As I’ve noted before, Microsoft has a well-established support lifecycle for its software products. It’s basically an agreement that the company makes with everyone who commits to Windows. The terms of that agreement don’t change often, which is an important assurance for business customers who tend to be conservative in their approach to upgrades.

For the next six months and counting, Microsoft will officially offer support for five versions of Windows for desktop and notebook PCs. Here’s the rundown, starting with the newest member of the family:

Windows 8.1

Microsoft’s official Windows 8.1 Support Lifecycle Policy treats this update as if it were a service pack for Windows 8. That means the lifecycle calculations start when Windows 8 shipped, in 2012.

This version is currently available only for Microsoft’s volume licensing customers, MSDN and TechNet subscribers, and hardware OEM partners. It will be available to the public as a free update and in retail packages on October 18, 2013.

Mainstream support ends: January 9, 2018

Extended support ends: January 10, 2023

Windows 8

Windows 8 is fully supported today, but you need to update to Windows 8.1 to remain supported under the Windows 8 lifecycle. The deadline is “two years after the General Availability of the Windows 8.1 update,” or October 18, 2015.

The same policy applies to Windows Server 2012 and 2012 R2 (equivalent to Windows 8.1).

Mainstream support ends: see Windows 8.1

Extended support ends: see Windows 8.1

Windows 7 Service Pack 1

This is currently the most popular release of Windows, and promises to hold that top spot for a long, long time. The following support dates require that you install Service Pack 1 (Windows 7 RTM support ended in April 2009).

Note that these dates are identical for Windows Server 2008 R2.

Mainstream support ends: January 13, 2015

Extended support ends: January 14, 2020

Windows Vista Service Pack 2

Fun fact: As of October 2013 the much-reviled Windows Vista was still in use on more computers than any version of OS X. The mainstream support phase ended in 2012, but extended support will continue for a few more years.

Mainstream support ends:No longer supported

Extended support ends: April 11, 2017

Windows XP Service Pack 3

Windows XP is more than 12 years old. It’s midway through a year-long farewell tour , counting down to April 8, 2014, when Microsoft officially ends its support. XP lived longer than any version of Windows ever, getting multiple extensions on its retirement date to placate customers who said no to Vista. But April 2014 is the end of the road. XP will not get a last-minute reprieve.

Mainstream support ends:No longer supported

Extended support ends: April 8, 2014

Let me say that again: Microsoft will not extend the support deadline for XP. If you're still relying on XP, you should have a plan to switch to a supported platform, whether it's from Microsoft or someone else.

April 8, 2014 is a deadline. It's not a death sentence. PCs running XP will not stop working when the clock runs out. In fact, XP diehards won’t notice anything different except an eerie quiet on the second Tuesday of each month. Newer versions, including Windows Vista, Windows 7, and Windows 8, will continue to get security patches and bug fixes via Windows Update, but not XP. When the extended support period ends, so do those updates. (Large enterprise customers who have custom support agreements with Microsoft and who are willing to pay a very steep price for the privilege might be able to get custom updates after the official end of support. But consumers and small businesses will not have that option.)

Meanwhile, it’s become obvious that Windows 7 is the new Long Term Support version. If you’re concerned that Microsoft is going to try to kill off Windows 7, you can relax. It’s not time to start a “Save Windows 7” movement yet. You’ve got many years to ponder what comes next.

A couple of footnotes:

Windows RT doesn't exactly fit in the support policy, because it's sold only in combination with ARM-based hardware. Updates to both the operating system and the included Office 2013 programs are delivered through Windows Update. It cannot be upgraded to a different operating system. After a full year on the market, Microsoft's official Windows RT Product Support Lifecycle Policy FAQ still doesn't list any support lifecycle dates. Instead, it simply says:

Microsoft will make software updates, including security updates, available for Windows RT. Additional information regarding the Windows RT lifecycle policy will be communicated as available.

And if you're curious about Server versions, the clock isn't ticking yet, but it's time to get just a little bit nervous. Extended support for Windows Server 2003 ends on July 14, 2015. That's less than two years away.

Next page: Office support dates and how the Support Lifecycle works

[For details about Windows support dates, see the previous page.]

Office support dates

The Office support lifecycle works just like Windows. Here are the support dates for each current member of the Office family:

Office 2013

This is the current release of Office, with a schedule that goes roughly three months past that of Windows 8. Mainstream support ends on April 10, 2018, with extended support continuing until April 11, 2023. (As a side note: the subscription-based Office 365 automatically updates itself to the most recent release, so it has no support lifecycle.)

Office 2010 Service Pack 2

Support for Service Pack 1 ends on October 14, 2014. But once you install Service Pack 2, you'll find this version is in its prime, with end of support dates that are 6 months after those of Windows 7. Mainstream support ends October 13, 2015, and the end date for extended support is not until October 13, 2020.

Office 2007 Service Pack 3

Earlier service pack release are no longer supported, and this group of products has already passed the end of mainstream support. Extended support ends on October 10, 2017.

Office 2003 Service Pack 3

This old-timer is on the same calendar as Windows XP, with mainstream support already ended and extended support slated to end on April 8, 2014.

How the support lifecycle works

For all versions of Windows and Office, Microsoft provides at least five years of mainstream support, followed by another five years of extended support. These lifecycles apply equally to business and home versions of Windows and Office. Service packs have separate end-of-support dates. For example, beginning next week you’ll need to be running Service Pack 1 to get support for Windows 7. (There’s an exhaustive FAQ if you want to dig deeper into this stuff.)

Generally, “supported” means you have access to at least one type of assisted support option (possibly paid) and no-charge security updates through channels like Windows Update and the Download Center.

The calculations start with the general availability (GA) date for each product. The official date of retirement for support is the second Tuesday in the first month of the quarter following that anniversary (which also happens to be Patch Tuesday). That grace period typically means a few weeks or months of extra support tacked on at the end of the five- and ten-year support cycles for each product.

For Windows 7, you can do the math yourself. The GA date for all Windows 7 editions was October 22, 2009. Five years after that date is October 22, 2014. The next calendar quarter begins in January, 2015, and the second Tuesday of that month is January 13. So, that's when mainstream support is scheduled to end. Extended support for business all editions goes an extra five years, until January 14, 2020, which happens to be the second Tuesday of that month. (Those calculations don't work for Windows XP, whose end-of-life date was extended artificially.)

To find the end-of-support date for any Microsoft product, use the Microsoft Product Lifecycle Search page, the product family index, or the full A-Z product index to get the official answer. When you find the entry for a specific product, you can see the general availability date, the retirement dates for mainstream and extended support, and retirement dates for service packs.